picking the right imac specifications

I'm about to buy a new 15" imac laptop and want to know where to put my money for most bang for buck.

I do a lot of animation and video editing with Premiere and Photoshop open at once.

I wonder if an expert can offer some guidance.

my choices:

1. the processor is 8-core 9th generation Intel Core i9, but I can chose either 2.3 GHz with boost to 4.8 or 2.4 GHz with boost to 5.0.  is that worth the $180 upgrade?

2. I do think I should pay for 32GB RAM over 16, right?

3. Last, the graphics card.  can you advise on choice:

Radeon Pro 560X with 4GB of GDDR5 memory

or for $225 more: Radeon Pro Vega 16 with 4GB of HBM2 memory

and for $310 total more: Radeon Pro Vega 20 with 4GB of HBM2 memory

which upgrades really pay off?  and if i want photoshop and premiere working very smoothly and quickly together, should i just be going for the desktop with more power?